yggdrasil/public/js/lightbox.js
xfy 75b9080df8 refactor(post-cover): use raw blur-img structure as single lightbox image
drop ImageViewer; render .blur-img with a lightbox-single class (the
class, not a data attribute, because Dioxus' typed span elements reject
arbitrary data-* attrs). lightbox.js now keys single-mode off the
lightbox-single class instead of data-single. cover uses ?w=20
placeholder + ?w=1200 display; SSR writes --ar from real dimensions.
2026-06-23 15:48:02 +08:00

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JavaScript
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(function () {
"use strict";
// ============ 工具函数 ============
function prefersReducedMotion() {
return (
window.matchMedia &&
window.matchMedia("(prefers-reduced-motion: reduce)").matches
);
}
// 读取元素当前在视口里的 rect用于飞行起点/终点)。
function rectOf(el) {
return el.getBoundingClientRect();
}
// 计算图片在视口居中、contain 适配后的目标 rect。
// naturalW/H: 图片真实像素尺寸vw/vh: 视口尺寸。
function fitCentered(naturalW, naturalH, vw, vh) {
var maxW = vw * 0.92;
var maxH = vh * 0.88;
var scale = Math.min(maxW / naturalW, maxH / naturalH, 1);
var w = naturalW * scale;
var h = naturalH * scale;
return {
x: (vw - w) / 2,
y: (vh - h) / 2,
w: w,
h: h,
};
}
// 把目标 rect 转成 transform 字符串(基于 naturalW/H 做缩放)。
// transform-origin 为 top left见 CSStranslate 到 rect 左上角后 scale。
function transformFor(rect, naturalW, naturalH) {
var sx = rect.w / naturalW;
var sy = rect.h / naturalH;
return (
"translate(" +
rect.x +
"px," +
rect.y +
"px) scale(" +
sx +
"," +
sy +
")"
);
}
// 原图 URL = data-src 去 query。data-src 形如 "/uploads/x.webp?w=800"。
function originalUrl(dataSrc) {
return (dataSrc || "").split("?")[0];
}
// ============ 懒加载 ============
// 为单个 .blur-img 容器初始化高清图懒加载。
// IO 进入视口后把 data-src 写入 src加载完成加 is-loaded 触发 CSS 淡入。
function initLazyLoad(container) {
var fullImg = container.querySelector(".blur-img-full");
if (!fullImg) return;
if (container.getAttribute("data-blur-init")) return;
container.setAttribute("data-blur-init", "true");
var fullSrc = fullImg.getAttribute("data-src");
if (!fullSrc) return;
fullImg.addEventListener("load", function () {
this.classList.add("is-loaded");
});
if ("IntersectionObserver" in window) {
var io = new IntersectionObserver(
function (entries) {
entries.forEach(function (entry) {
if (entry.isIntersecting) {
fullImg.src = fullSrc;
io.unobserve(container);
}
});
},
{ rootMargin: "200px" }
);
io.observe(container);
} else {
fullImg.src = fullSrc;
}
}
// ============ 图像收集 ============
// 收集所有 selectors命中的 .blur-img 节点。
// gallery: 正文图组成图集singles: 带 lightbox-single class 的单张图(如封面)。
function collectImages(roots) {
var gallery = [];
var singles = [];
for (var i = 0; i < roots.length; i++) {
var nodes = roots[i].querySelectorAll(".blur-img");
for (var j = 0; j < nodes.length; j++) {
var n = nodes[j];
if (n.classList.contains("lightbox-single")) {
singles.push(n);
} else {
gallery.push(n);
}
}
}
return { gallery: gallery, singles: singles };
}
// ============ 灯箱状态与开/关 ============
// 当前灯箱状态(同时只允许一个灯箱)。
var state = null;
function openLightbox(originNode, gallery, index) {
if (state) closeLightbox(true);
var fullImg = originNode.querySelector(".blur-img-full");
if (!fullImg) return;
var dataSrc = fullImg.getAttribute("data-src") || "";
var origSrc = originalUrl(dataSrc);
var altText = fullImg.getAttribute("alt") || "";
var isSingle =
originNode.classList.contains("lightbox-single") ||
gallery.length === 0;
var vw = window.innerWidth;
var vh = window.innerHeight;
// 建 DOM
var overlay = document.createElement("div");
overlay.className = "lightbox-overlay";
overlay.setAttribute("role", "dialog");
overlay.setAttribute("aria-modal", "true");
overlay.setAttribute("aria-label", "图片预览");
overlay.setAttribute("tabindex", "-1");
var img = document.createElement("img");
img.className = "lightbox-img";
img.setAttribute("alt", altText);
var caption = document.createElement("figcaption");
caption.className = "lightbox-caption";
caption.textContent = altText;
if (!altText) caption.style.display = "none";
var counter = document.createElement("div");
counter.className = "lightbox-counter";
if (isSingle || gallery.length === 0) {
counter.style.display = "none";
} else {
counter.textContent = index + 1 + " / " + gallery.length;
}
// 图集模式(>1 张)才加左右导航箭头;单张不显示。
var prevBtn = null;
var nextBtn = null;
if (!isSingle && gallery.length > 1) {
prevBtn = document.createElement("button");
prevBtn.className = "lightbox-nav lightbox-prev";
prevBtn.setAttribute("type", "button");
prevBtn.setAttribute("aria-label", "上一张");
prevBtn.textContent = "\u2039";
nextBtn = document.createElement("button");
nextBtn.className = "lightbox-nav lightbox-next";
nextBtn.setAttribute("type", "button");
nextBtn.setAttribute("aria-label", "下一张");
nextBtn.textContent = "\u203a";
}
overlay.appendChild(img);
overlay.appendChild(caption);
overlay.appendChild(counter);
if (prevBtn) overlay.appendChild(prevBtn);
if (nextBtn) overlay.appendChild(nextBtn);
document.body.appendChild(overlay);
state = {
overlay: overlay,
img: img,
caption: caption,
counter: counter,
prevBtn: prevBtn,
nextBtn: nextBtn,
originNode: originNode,
gallery: gallery,
index: index,
isSingle: isSingle,
openScrollY: window.scrollY,
origSrc: origSrc,
altText: altText,
closing: false,
reduced: prefersReducedMotion(),
scrollHandler: null,
keyHandler: null,
};
// 焦点移入灯箱
overlay.focus();
// 立即绑定交互(不等图片加载):加载期间 Esc/滚动/点背景也须可关闭。
bindInteractions();
// 图片加载后再做动画naturalW/H 要等加载)
var start = function () {
if (!state) return; // 加载前可能已被关闭
var naturalW = img.naturalWidth || img.clientWidth || 1;
var naturalH = img.naturalHeight || img.clientHeight || 1;
var originRect = rectOf(originNode);
// reduced-motion直接淡入居中
if (state.reduced) {
img.style.opacity = "0";
var target = fitCentered(naturalW, naturalH, vw, vh);
img.style.transform = transformFor(target, naturalW, naturalH);
img.style.left = "0";
img.style.top = "0";
overlay.style.opacity = "0";
// 下一帧淡入
requestAnimationFrame(function () {
if (!state) return;
overlay.style.transition = "opacity 200ms ease-out";
img.style.transition = "opacity 200ms ease-out";
overlay.style.opacity = "1";
img.style.opacity = "1";
});
return;
}
// 首帧:放到 originRect 位置与尺寸,透明
img.style.transition = "none";
img.style.left = "0";
img.style.top = "0";
img.style.transform = transformFor(originRect, naturalW, naturalH);
img.style.opacity = "0";
overlay.style.opacity = "0";
// 下一帧:飞到居中
requestAnimationFrame(function () {
if (!state) return;
var tgt = fitCentered(naturalW, naturalH, vw, vh);
img.style.transition =
"transform 250ms ease-out, opacity 250ms ease-out";
overlay.style.transition = "opacity 250ms ease-out";
img.style.transform = transformFor(tgt, naturalW, naturalH);
img.style.opacity = "1";
overlay.style.opacity = "1";
});
};
if (img.complete && img.naturalWidth) {
start();
} else {
img.addEventListener("load", start, { once: true });
}
img.src = origSrc;
}
function closeLightbox(immediate) {
if (!state || state.closing) return;
state.closing = true;
cleanupInteractions();
var s = state;
var naturalW = s.img.naturalWidth || s.img.clientWidth || 1;
var naturalH = s.img.naturalHeight || s.img.clientHeight || 1;
var originRect = rectOf(s.originNode); // 实时读,处理期间滚动过的情况
if (s.reduced || immediate) {
removeOverlay();
return;
}
// 飞回 originRect
s.img.style.transition =
"transform 250ms ease-out, opacity 250ms ease-out";
s.overlay.style.transition = "opacity 250ms ease-out";
s.img.style.transform = transformFor(originRect, naturalW, naturalH);
s.img.style.opacity = "0";
s.overlay.style.opacity = "0";
var done = function () {
removeOverlay();
};
// 250ms 兜底,避免 transitionend 不触发
setTimeout(done, 280);
s.img.addEventListener("transitionend", done, { once: true });
}
function removeOverlay() {
if (!state) return;
var prev = state.originNode;
if (state.overlay && state.overlay.parentNode) {
state.overlay.parentNode.removeChild(state.overlay);
}
state = null;
// 焦点归还:.blur-img 是 span 不可聚焦,让其内部 full img 获得焦点
if (prev) {
var f = prev.querySelector(".blur-img-full");
if (f) {
f.setAttribute("tabindex", "-1");
f.focus();
}
}
}
// ============ 图集切换 ============
// 图集切换淡入淡出不飞行。newIndex 循环(首尾衔接)。
function gotoIndex(newIndex) {
if (!state || state.isSingle) return;
var s = state;
if (!s.gallery || s.gallery.length === 0) return;
if (newIndex < 0) newIndex = s.gallery.length - 1;
if (newIndex >= s.gallery.length) newIndex = 0;
if (newIndex === s.index) return;
var newNode = s.gallery[newIndex];
var fullImg = newNode.querySelector(".blur-img-full");
if (!fullImg) return;
var origSrc = originalUrl(fullImg.getAttribute("data-src") || "");
var altText = fullImg.getAttribute("alt") || "";
// 淡出当前图
s.img.style.transition = "opacity 150ms ease-out";
s.img.style.opacity = "0";
// 150ms 后换图淡入
var swap = function () {
if (!state) return; // 切换中可能已关闭
var fade = function () {
if (!state) return;
s.img.style.transition = "opacity 150ms ease-out";
s.img.style.opacity = "1";
};
if (s.img.complete && s.img.naturalWidth) {
// 缓存命中,直接淡入
s.img.src = origSrc;
fade();
} else {
s.img.addEventListener("load", fade, { once: true });
s.img.src = origSrc;
}
s.caption.textContent = altText;
s.caption.style.display = altText ? "" : "none";
s.counter.textContent = newIndex + 1 + " / " + s.gallery.length;
// 更新 originNode 为新图,使后续关闭/滚动关闭飞回新图位置
s.originNode = newNode;
s.index = newIndex;
s.openScrollY = window.scrollY; // 重置滚动关闭基线
};
setTimeout(swap, 150);
}
// ============ 交互绑定 ============
function bindInteractions() {
var s = state;
if (!s) return;
// 点背景关闭(点图片本身不关,因箭头在图上、避免误关)
s.overlay.addEventListener("click", function (ev) {
if (state && ev.target === state.overlay) closeLightbox(false);
});
// 滚动驱动关闭:任何 scroll 都触发,用 scrollY 偏移算进度。
// 关键:逐帧读 originNode 实时 rect文章滚多少图就回多少。
s.scrollHandler = function () {
if (!state) return;
var st = state;
if (st.closing) return;
var dy = Math.abs(window.scrollY - st.openScrollY);
if (st.reduced) {
// reduced-motion立即关
closeLightbox(true);
return;
}
var progress = Math.min(dy / 120, 1);
var naturalW = st.img.naturalWidth || st.img.clientWidth || 1;
var naturalH = st.img.naturalHeight || st.img.clientHeight || 1;
var originRect = rectOf(st.originNode);
var target = fitCentered(
naturalW,
naturalH,
window.innerWidth,
window.innerHeight
);
// 在 originRect 与居中 target 之间按 progress 线性插值
var cur = {
x: target.x + (originRect.x - target.x) * progress,
y: target.y + (originRect.y - target.y) * progress,
w: target.w + (originRect.w - target.w) * progress,
h: target.h + (originRect.h - target.h) * progress,
};
st.img.style.transition = "none";
st.img.style.transform = transformFor(cur, naturalW, naturalH);
st.img.style.opacity = String(1 - progress);
st.overlay.style.opacity = String(1 - progress);
if (progress >= 1) {
// 已飞回原位:文章停在当前滚动位置,移除灯箱
st.closing = true;
cleanupInteractions();
removeOverlay();
}
};
window.addEventListener("scroll", s.scrollHandler, { passive: true });
// 键盘Esc 关;图集模式 ←→ 切换
s.keyHandler = function (ev) {
if (!state) return;
if (ev.key === "Escape") {
closeLightbox(false);
} else if (!state.isSingle && state.gallery.length > 1) {
if (ev.key === "ArrowLeft") {
ev.preventDefault();
gotoIndex(state.index - 1);
} else if (ev.key === "ArrowRight") {
ev.preventDefault();
gotoIndex(state.index + 1);
}
}
};
document.addEventListener("keydown", s.keyHandler);
// 图集导航箭头点击stopPropagation 防止冒泡到 overlay 触发关闭)
if (s.prevBtn) {
s.prevBtn.addEventListener("click", function (ev) {
ev.stopPropagation();
if (state) gotoIndex(state.index - 1);
});
}
if (s.nextBtn) {
s.nextBtn.addEventListener("click", function (ev) {
ev.stopPropagation();
if (state) gotoIndex(state.index + 1);
});
}
}
function cleanupInteractions() {
if (!state) return;
if (state.scrollHandler) {
window.removeEventListener("scroll", state.scrollHandler);
state.scrollHandler = null;
}
if (state.keyHandler) {
document.removeEventListener("keydown", state.keyHandler);
state.keyHandler = null;
}
}
// ============ 初始化入口 ============
window.__initLightbox = function (selectors) {
// selectors 可以是字符串、字符串数组
var sels = Array.isArray(selectors) ? selectors : [selectors];
var roots = [];
for (var i = 0; i < sels.length; i++) {
var found = document.querySelectorAll(sels[i]);
for (var j = 0; j < found.length; j++) roots.push(found[j]);
}
// 先对所有图片做懒加载(图集与单张都做)
var collected = collectImages(roots);
var everyone = collected.gallery.concat(collected.singles);
for (var k = 0; k < everyone.length; k++) {
initLazyLoad(everyone[k]);
}
// 正文图:带 index
var gallery = collected.gallery;
for (var g = 0; g < gallery.length; g++) {
(function (node, idx) {
node.addEventListener("click", function (e) {
e.preventDefault();
openLightbox(node, gallery, idx);
});
})(gallery[g], g);
}
// 单张图封面index = nullgallery 传空数组表示单张
for (var si = 0; si < collected.singles.length; si++) {
(function (node) {
node.addEventListener("click", function (e) {
e.preventDefault();
openLightbox(node, [], null);
});
})(collected.singles[si]);
}
};
})();